1. Field of the Invention
The present invention relates to a touchscreen.
2. Description of the Related Art
A liquid crystal display (LCD) or an organic electroluminescent display device has been known as a display device.
The organic electroluminescent display device includes a structure in which, for example, pixel circuits, organic light-emitting diodes (OLEDs), a sealing film, and the like are stacked on a substrate made of glass or a resin film. A display surface protective film is bonded on the sealing film with, for example, an adhesive or the like.
FIG. 10 is a schematic partial sectional view of a conventional organic electroluminescent display device. Structures such as thin film transistors (TFTs) 202 constituting pixel circuits and wirings 204 are formed on a substrate 200. On the structures, OLEDs 206 are formed.
The OLED 206 is configured to include a lower electrode 208, an organic material layer 210, and an upper electrode 212. The organic material layer 210 includes a light-emitting layer. The lower electrode 208 and the upper electrode 212 interpose the organic material layer 210 therebetween. The lower electrode 208 constitutes an anode electrode (anode) of the OLED 206. The upper electrode 212 constitutes a cathode electrode (cathode) of the OLED 206. The upper electrode 212 is formed in common to pixels in the entire display area, and a common voltage is applied from a drive portion to the upper electrode 212. On the other hand, the lower electrode 208 is formed for each of the pixels.
A sealing film is stacked on the surface of the OLED 206. The sealing film can have a multilayer structure composed of two layers of inorganic films 214 and 216 and an organic film 215 interposed therebetween.
The organic electroluminescent display device includes a connection terminal area 220 adjacent to the display area. In the connection terminal area 220, the wirings 204 extracted from the display area and connection terminals 222 for connecting the wirings to an external circuit are disposed. A flexible printed circuit (FPC) is connected to the connection terminals 222. The organic electroluminescent display device operates with electric signals supplied from the external circuit via the FPC.
As one of forms of the display device, a touchscreen including a display panel and a touch sensor combined together is present. Examples of the touchscreen include an on-cell type touchscreen having a structure in which the touch sensor and the display panel are bonded together, and an in-cell type touchscreen in which the structure of the touch sensor is built into the display panel.
In the on-cell type touchscreen, wirings for external connection are prepared separately for the touch sensor and the display panel. Therefore, an FPC connected to the touch sensor and an FPC connected to the display panel are basically different. In this regard, in an in-cell type LCD, by connecting a wiring layer of the touch sensor and a wiring layer of the LCD with a contact structure using a through hole, wirings for external connection of the touch sensor and wirings for external connection of the LCD can be formed of one wiring layer, or the wirings for external connection can be shared, and thus connection with the external circuit can be made using one FPC.